Promises Written in Stone
by scorchedtrees
Summary: They have separate duties to fulfill, but someday they will meet again. Rivetra.


_A/N: This is just SnK in the Psycho-Pass world, or more specifically, a Rivetra possibility in the Psycho-Pass world._

* * *

><p>The sound of her shoes hitting the steps two at a time is loud in the echoey silence of the stairwell. The emptiness of each level in the tower is stifling and she tries to force herself past it, to focus her mind on each detail around her, the grooves in the walls and the scratches scuffing the concrete and the cold steel of the metal railings, but each floor she travels down only tightens her throat and makes the lump in her chest grow. Her breath comes out in uneven spurts and both guns feel heavy—the Dominator in her hands, the pistol wedged in her back pocket.<p>

She knows what she will find when she reaches the bottom, and it makes her run all the faster at the same time it makes her want to turn around and flee.

The door at the end of the hallway in the true basement of Sina Tower is ajar, white light spilling through the crack, and though she has been here once already, the sight of that entrance makes her remember what is beyond it with fresh horror all over again. She stops to breathe deeply, air rattling shakily through her nose and out her mouth, to close her eyes and prepare herself for what she will see before stepping through.

It is exactly as she left it last time—the bright glass chambers, the constant humming of computers, and worst of all, the endless rows of containers, each housing a complete human brain. She watches, eyes wide in fascination and disgust, as machines carry the containers back and forth, constantly working, scanning and processing data, an entire country's worth of human lives being judged by a few hundred.

She is not here to witness the atrocious truth of the TITAN system again though; she is here for an entirely different reason. She whirls around, searching the small area, looking for the one person she trusts with the secrets of the system, the person she thought would be here—but she is alone.

Levi is gone.

x.

"You're the Inspector," he says, his cool gaze flicking briefly in her direction before moving away again. "You don't like my methods, it's your job to shoot me."

They're the first words the short Enforcer has spoken since he stepped off the police van with the other three; she only blinks at him as he walks away. Beside her, the sandy-haired Enforcer snorts.

"That's Levi Ackerman," he says. "He's the best at his job, but he's also an ass." His voice has a tinge of admiration in it though. "I'm Auruo Bossard." Before she can respond, he adds, "We'd better catch up with him, huh?"

She nods and they hurry down the street after Ackerman. A cool wind nips at Petra's face and she tugs on the collar of her shirt, wishing she had a jacket to wear over her suit like the other Enforcers do, or even a trenchcoat like her new partner's. She thinks briefly of Smith's warm words and assessing eyes and wonders what exactly he expects from her first mission.

The Dominator feels like a burden in her hands—she has used one in training before, but never in the real world with real potential targets around her. Something lurches in the corner of her vision and she points the gun at it instantaneously, but then she sees the drunkard by the side of the road and TITAN's directionalized voice sounds in her mind: _Crime Coefficient under fifty. Not an enforcement target. Locked trigger._

She lowers the gun and continues to follow Bossard, but staring at his scruffy hair and partially shaved head, curiosity propels her to raise the Dominator again, this time at his back. _Crime Coefficient over 140. A target of the Criminal Investigations Department. Released safety._

_He could be as dangerous as the man we're hunting,_ she realizes as they continue on in silence. Ackerman seems to have disappeared and Bossard looks over his shoulder occasionally to beckon her forward. _He seems so normal, but I guess there's a reason Inspector Smith told me to treat them with caution._

Unbidden, the short Enforcer springs to mind—his bored face and scowling mouth, his flat gaze and the low tones of his voice. She smiles despite herself; she'll definitely treat that one with caution.

x.

"You said he would be here," she spits. She's not sure whom she's talking to, the hundreds of human brains behind the glass or the gun in her hands, pulsing with the life of the TITAN system—the life Levi hated so much. "Where is he?"

She almost doesn't expect a response, but at the same time she knows she'll get one—and she's been both dreading and looking forward to it. Ever since that fateful moment a few days ago (_only a few days,_ she thinks, _but it feels so long_) when she lost half her team to TITAN and the other half to the truth, she's been waiting to be contacted again, because if she truly is the only person alive who knows how the system is run besides Levi, they won't leave her alone.

She is still alive for a reason—they want something from her.

"Petra Ral," the voice croons in her ear. She shivers; were it not robotic, she could swear it sounds delighted. "You have come."

"You said he would be here!" She stares straight forward, her hand free of the Dominator curling into a fist, resisting the urge to pound the glass. The pistol is in her pocket, and if she grabbed it perhaps she could shoot a few of the brains before anyone comes to deal with her—but no, she must remain calm; she needs answers. Even if she is alone, even if she will never see Levi again, she needs to be smart and stay alive.

"He is gone," TITAN tells her.

"Gone? Like you let him walk out of here or like you disposed of him?"

"He will not be returning," the voice says, and she sucks in a breath, trying not to shout. "He is gone."

x.

"Don't do anything stupid," Petra whispers, echoing Gin's words from earlier. She doesn't expect Ackerman to hear her voice down the corridor, but she sees him nod, and then he slips in.

A beat, then—

"Do you always take a shit after killing someone, you fucking coward?"

She hears the crash of a door being forcefully kicked down a moment later and she is torn between gaping in shock and slapping a palm to her face in exasperation. _How is this anything but stupid?_ she wonders as Ackerman continues to jeer—if one can jeer in a bland tone. He doesn't seem to care one iota what he's saying, but the words he speaks are all clearly intended to incite a strong reaction; a moment later, the other man comes bursting out of the restroom, face panicked, pushing past Petra as if she is not there and rushing down the corridor.

Ackerman walks out a moment later, hands in his pockets. She opens her mouth—to say what, she has no idea—but he speaks before she can. "Now he'll either do nothing or do exactly what he did before… if that's the case, watch out."

She remembers the words an hour later, sitting outside the factory chief's office, trying to glance occasionally at Ackerman without making it obvious. His jacket is off, his sleeves rolled up to the elbows, scrapes lining his arms and blood dripping from a cut on his face, but it is nothing compared to the rest of the blood dotting his shirt; he does not seem to feel any pain from his injuries though. When she closes her eyes she sees the hot white light of the Dominator's lethal eliminator, so she stares at the scratches on her own palms instead; she was lucky.

Ackerman is tapping his fingers against his thigh, quiet as Bossard and Gin laugh about something and Smith speaks to the chief inside. Schulz offers Petra a handkerchief, which she accepts with a grateful smile, and as she takes the cloth she looks past him to accidentally lock gazes with Ackerman. She looks away again quickly.

She remembers the way he stood by her side looking down at the woman on her first mission, the way he surprised her, but she also remembers the look in his eyes as he cornered the worker, the expression she could only classify as savage satisfaction, and she wonders if she can really trust him.

x.

"Then why am I here?" she asks. She tells herself to remain strong, but her voice sounds broken, even to herself. "Why did you summon me here?"

There is no immediate response. The adrenaline is fading from her body, leaving her heart stuttering and her mind racing, her legs shaky and her mouth dry. She was fully expecting Levi to be here, alive or in bloody pieces, and now that he has disappeared, she does not know what to do next, what he would want her to do next. She always thought they would figure it out together.

"Have you ever wondered why your Psycho-Pass hue is always so clear?" TITAN asks. "Have you ever wondered how your Crime Coefficient stays so low?"

She thinks of Erwin Smith and the mixture of despair and triumph in his blue eyes he was not completely able to hide right before they took him away, and the fact that he is now in a ward for latent criminals, undergoing therapy. She thinks he suspects far too much from her flimsy report, from its sketchy details and the impassive recounting of her teammates' deaths, and she recalls that his father died under similar suspicious circumstances when he was only a boy—and she has a feeling she is going to see him again soon in the Bureau, though perhaps not as a partner.

"No," she says, but the system that can measure her worth as a human being—by its own standards, anyway—can also tell when she is lying.

"You have always been an ideal student," it says. "Now you are an ideal citizen."

"Who are you to judge?" she snaps. "You're only a few hundred people out of millions. Who gave you the right to judge?"

"We cannot be judged," TITAN says, and with a shiver she realizes it is now speaking with the voice of hundreds. "So we are the judges."

x.

When Ackerman offers her a cigarette, she is so startled that she nearly takes it before catching herself.

"No thanks. I don't smoke," she says quickly, snatching her fingers back. He shrugs and sticks the tube back in his pocket.

"Suit yourself." He takes another drag on his own and blows smoke out into the air. The scent seeps into the humidity of the room and she stares at the wall past his shoulder rather than at his expressionless face, at the unnerving way his gaze is fixed on her or the chiseled muscles of his bare arms and chest, still gleaming with sweat after his workout.

She clears her throat when he does not say anything else. "I wanted to thank you," she says. She tries to speak the words lightly, casually, but something sticks in her throat and she can feel heat rising to her cheeks anyway. "I mean… you were just doing your job, but… I appreciated your methods." She shakes her head; she has given so many speeches in her years at school and now she can't even get a simple point across. "What I'm trying to say is… despite what everyone says about Enforcers, I believe we can truly work together as a team to deal with all sorts of situations in the field."

Ackerman studies her, his head tilted; his eyes slant towards the door, towards the Psycho-Pass scanner positioned above it. "Then you're a fool," he says.

She blinks. "Excuse me?"

"You heard me. You're a fool." He gestures to the scanner with his cigarette. "According to that, I might suddenly decide to burn you right now. Or I could just strangle you with my bare hands. Because I've got the potential for such criminal activities. And you don't. So we can never work together, not the way you want."

His smile is not a real smile; it's mocking, sardonic—and a façade, she can tell. He is testing her; on what, she has no idea, but he is testing her all the same.

"You're the fool if you think I'd believe you'd hurt me without a rational motive," she answers calmly, and is rewarded with a raised eyebrow.

"Hm," is all he says, but as he lifts the cigarette to his lips again, she thinks he may look vaguely pleased.

x.

"So why have you judged me as a good person and others as bad when there is no real difference between us?"

The voice that speaks in her ear this time is amused. "There is a very fundamental difference between you and others that makes you an ideal citizen in a country governed by the Psycho-Pass system."

She hardly agrees, but then again, she doesn't exactly agree with TITAN's existence in the first place, or at least its form of existence. Still, she scowls. "What difference?"

"The Psycho-Pass system uses cymatic scans to determine a person's mental health and stability," it says, as if it is something she does not know already. "Countless factors affect a person's state of mind—from deaths of close friends to the weather." Petra grits her teeth, wondering if it means to use certain recent events as an example to goad her. "Once a person's mental stability is affected negatively, that person may become more prone to violent, criminal activities."

"Get to the point," she snaps.

"But you, Petra Ral… TITAN has been analyzing you. You are capable of something very few are: not letting your emotions cloud your reason."

She mulls over the words for a moment before shaking her head. "That's not true," she says. "Many can do that."

"In small amounts, yes. But when one is truly affected, who can? It is not the amount of emotion displayed over an event that is taken into consideration but the long-lasting psychological effects. Your Enforcer friend was so angry over his friends' deaths, over discovering the truth to the way TITAN is run, that he has set out to destroy the system. The system killed your friends, yet you are still here."

Petra shakes her head again; she doesn't want to accept what she's hearing. But even as she tries to deny it, she cannot help admitting to herself that it is partially right—she watched Auruo, Erd, and Gunter die before her eyes for no reason other than that they stumbled upon TITAN's core, but the system runs the entire country, and it is the country she thinks of when she is tempted to join Levi in his quest.

"You are different, Petra Ral, and we want to study you."

x.

"What about Ackerman?"

She says the words nonchalantly, but Auruo—as he insisted on being called; "'Bossard' makes me sound old and I already look old enough for my age," he complained—eyes her contemplatively. "Why do you want to know?"

"Just curious." She shrugs. "I mean, you told me how you've been a latent criminal since you were a kid, and I know the other Enforcers used to be Inspectors a long time ago—so what about him?"

Auruo coughs and Petra gets the feeling he thinks he shouldn't tell her anything, but he really wants to. In the end he does anyway. "Levi… he was always an Enforcer. Got moved to Division One after a really fucked up case on his old team."

"What happened?"

He leans across the cafeteria table, chin propped on his hands, and Petra bites her lip to hold in a giggle; the posture makes her think of her civilian friends, sharing gossip after a long day at work. "I don't know the details, but there was a string of really gruesome murders, and one of the Enforcers on his old team was killed that way. Poor thing; she was just a little girl. He and another Enforcer found the culprit and strung him up the same way—naturally, their Crime Coefficients went up."

"But not enough to get them killed?"

"That's the thing. The other Enforcer's did and one of the Inspectors on their team shot him and he died, obviously—but Levi's stayed the same." Auruo looks equally fascinated and disturbed by the thought. "His has always been really high, but it never changes much and it never goes above 300. Even when he tried to attack the Inspector who shot his friend, the Dominator only paralyzed him."

"So he was moved to this Division afterwards?"

"Yeah. He's good at his job and Smith likes him, so Smith pulled some strings and Levi switched with one of the Enforcers who used to be here. The other Inspector before you came, Dawk, he didn't like him, and Levi often pissed him off or disobeyed his orders, but so far Levi seems fine with you." Auruo shoots her a sly look. "Probably 'cause you're young and pretty."

Petra knows he's teasing so she only rolls her eyes at him. Still, she can't stop thinking about his story long after dinner, and she wonders if part of the reason Ackerman spared the woman from their first mission has to do with the two dead Enforcers from his last team.

x.

"Then what about Levi? Why didn't you kill him that day too?"

There is no answer for a while. Petra only realizes how hard she is clenching her gun when she sees how white her knuckles have turned; she loosens her grip and notes with detachment how even her heartbeat is now. The system is working unceasingly behind her, but despite the continuous hum of energy and the jacket she has pulled over her shoulders, she feels cold.

"Do you know what it means to be criminally asymptomatic, Petra Ral?"

"Asymptomatic means to show no symptoms," she murmurs. "So to show no signs of being a criminal?"

If TITAN were a flesh-and-blood person before her, it would be smiling. "Very clever. Those who cannot be judged by the system, those who cannot be read by its scanners and analyzed by its algorithms, are called criminally asymptomatic."

Suddenly she understands, with a cold flash of clarity like a bucket of ice water poured down her back. _We cannot be judged. So we are the judges._ "All of you are criminally asymptomatic."

"Yes."

It is a hard concept to wrap her brain around; she cannot imagine people free of the system, even those who run it. "But that makes you even worse judges," she says slowly. "Some of you could have the potential to be serial killers, but no one will ever know because the system can't tell." Trying to reason it out makes her head pound. "The entire system is based on a lie, but a lie of this magnitude—if this gets out, the country will riot."

"And that is precisely why you have not joined your friend in his efforts to bring us down, precisely why you have kept your mouth shut. You are smart, and you consider the interests of everyone, not just a few."

"But Levi isn't criminally asymptomatic."

"Before his Crime Coefficient went up," TITAN says, "he could have been."

x.

"Do you know what TITAN stands for?"

She blinks at the sudden change in topic but goes along with it; she's found that no matter what her conversations with Ackerman center around, she always learns something new. "Of course. It's one of the first things they teach in school."

She's always pleased when Smith takes two Enforcers and leaves her with Ackerman and someone else, usually Auruo, when they're working on a case; right now Schulz is scouting as she and Ackerman hang back, waiting for his signal to enter the building. She thinks she likes talking to Ackerman too much, but no one has told her off for extended contact with the Enforcers yet so she does not stop.

"Most people tend to forget, but you weren't the top student in the academy for nothing, I guess." The look he sends her way could be construed as one of esteem.

"Technology, Insight, Assessment, Neutrality." She grins. "Though everyone said we should just call it TITANS. S for System or Surveillance."

"Or 'shit,'" Ackerman says, surprising a laugh out of her. "But a titan in general is something of great strength or importance, so I suppose the creators of the system liked that too."

Despite the light tone of his voice, she can sense something stronger brimming underneath, the force of his views on the subject, and she wonders not for the first time exactly how he became an Enforcer in the first place and why he doesn't seem to view the Inspector and Enforcer relationship the way everyone else does. Not that she minds; she likes talking to him and the other Enforcers on her team, and if Smith trusts them, then she can too. They may be latent criminals but she knows they will not hurt her.

"Though the letters could just stand for anything," Ackerman says, interrupting her thoughts. "The words don't mean anything."

"But they stand for exactly what the system does, don't they?"

"Not really." His lip curls into a sneer. "That's what they want you to believe. Neutrality my ass; the system favors people."

There is a story in there, she knows, but before she can ask for it Schulz's voice crackles through her earpiece and they slip out of the alleyway and towards the building, conversation put aside in favor of work. She stores his words in her memory to pull out later though; she wants to know all she can about her teammates and if Ackerman does not tell her anything then she will figure things out herself.

x.

"According to your logic, anyone could be criminally asymptomatic then," Petra says. "Like Auruo. Auruo was always a latent criminal and he doesn't remember anything other than the facility." _Didn't,_ she corrects herself in her mind. The reminder is still painful.

"Auruo Bossard came from a large family," TITAN says. "He was the only one who displayed criminal tendencies as a child."

"By doing what?" she snaps. "Refusing to eat his baby food? Stealing a sibling's rattle?"

"You could never hope to understand. The way a person's Psycho-Pass and Crime Coefficient are determined is too complicated for a human mind to comprehend."

"So a couple hundred criminally asymptomatic human minds, they can do it?"

"You understand," the system says, either completely missing her sarcasm or choosing to ignore it. She figures it's the latter.

"So Levi wasn't a latent criminal, and then he was… what's your point? If the way his Crime Coefficient went up would be too complicated for me to get, then why are you mentioning it at all?"

"A person's Crime Coefficient is determined by many factors, both internal and external. Auruo Bossard's Crime Coefficient went up this way. Levi Ackerman… his Crime Coefficient was largely influenced by one unique external factor."

x.

"That one," he says suddenly, pointing. Hanji hits a button to pull the file out of the server.

"The last time he was caught by the scanners was weeks ago, and in the presence of the victim," Petra says as the data flashes onscreen. "His Psycho-Pass hadn't deteriorated to the point of needing therapy, but you can see the hue beginning to warp… right there."

"Check his cards and bank accounts," Ackerman says. "See if he made any suspicious purchases in the last week. Put a flag on him; if he shows up again the scanners will alert the system."

"On it, shorty."

He flicks Hanji's ponytail irritably at that, but Petra catches a hint of affection in the gesture. She hides a smile as Hanji's fingers click across the keyboard.

"I need to learn how to deduce things like you," she says that night in the office. Smith is at a meeting with the Chief and the others have left already; only she and Ackerman remain. "I wouldn't have thought to consider the murder from that perspective—it's clever and we wouldn't have found him so quickly if you hadn't figured out it was a grudge."

"You don't need to learn, Ral," Ackerman says. She kind of likes the way he drawls her last name; she wonders briefly what her first would sound like in his voice. "That's why there are Enforcers. And your job is to make sure we don't cross the line and do these things we can think of."

"But we're detectives," she points out. "We're all people who want to solve crimes and help maintain a normal society and we all have functioning brains, so I might as well use mine as best as I can." She shrugs. "Everyone calls Enforcers hunting dogs and Inspectors the masters, but Smith doesn't seem to think that way and Division One has always closed the most cases."

She stops when she sees how Ackerman is staring at her; when she first met him she would have called this expression apathetic, but now she can see curiosity and disbelief lurking in the depths of his gray irises. "Hm," he says, more to himself than her. "You're not worried about your Psycho-Pass hue?"

"What's there to be worried about? I want to help people, not harm them."

He coughs something that might be a laugh. "Can't argue with that." He sticks a hand into his pocket and scowls when it comes out empty; she remembers watching Hanji and Erd—she can't really think of any of them except Ackerman by their last names anymore—hide his cigarettes and she tries to keep a blank face.

"So you'll give me a few pointers?"

"Sure," he says, fingers drumming against his desk now, "though people are all the same, really. Predictable. It's easy to figure out what they all want." He frowns and his fingers pause in the middle of their rhythm. "Most people, anyway."

It is the pause that piques her interest. "Most people?" she repeats.

Ackerman's gaze feels like a test at that moment, a test she did not expect, but after a moment it wanders away and she feels like she passed, somehow. "Before I got sent to a facility," he says, and she realizes he means before he became a latent criminal, "I lived with a relative. Uncle, maybe, though he just told me to call him by name. He was… different."

"Different how?"

"Not in a good way." He says the words flippantly like they don't really matter, but she hears something dark in them, something twisted, and she suppresses a shiver. "His Crime Coefficient was ideal, his Psycho-Pass hue clear as fuck, but he taught me… well, he was messed up. Did all this shit with no purpose. Never knew what he was thinking. I lived with him until I was eight."

"And… ?"

"And one day he just disappeared."

x.

She sits cross-legged on the cold hard ground, her back to the glass chambers. She lays both guns by her feet and wonders if the worth of inanimate objects can be measured as well. The core of the system thrums with activity behind her, and she closes her eyes and listens as TITAN tells her a story.

"There was a man," it says, "who found that no matter what he thought or said or did, his Psycho-Pass hue was always pure white."

"He was criminally asymptomatic," Petra says. There is something heavy lodged in her heart; she knows where this story is going.

"He decided to experiment, to see how much he could get away with. He committed minor crimes—in secret at first, then in front of scanners. He caused public disturbances in areas swarming with drones. Never once was he picked up by the system."

She does not say anything; it is futile to mention how flawed the system is at this point. She wonders how she never noticed it before, especially with the Dominator in her hands, letting herself shoot whomever it told her to. Her naïveté feels like ages ago.

"The first time he took a human life, his Crime Coefficient dropped to zero."

"Shouldn't he be eliminated then? Are there people like this judging the rest of the human race?"

"It is precisely because of his unpredictability that he can accurately assess others," TITAN says. "But this man did one last experiment before we took him."

"What was it? Did he murder a baby in front of its mother?" Her voice drips with sarcasm. "Destroy a drone in front of a scanner?"

"No," is the answer, unaffected as always. "He attempted to make someone like him."

x.

She wonders if she is the first Inspector to go out with an Enforcer when it is unrelated to a case; she wonders what Smith would say if he knew. She hasn't had much contact with the other Divisions but she knows the other Inspectors keep their Enforcers on much tighter leashes (_pun unintentional,_ she thinks ruefully).

But Hanji mentioned the other day that it would be Ackerman's birthday on Christmas, and though the meaning of the holiday has long been forgotten, it is still a day to be celebrated. Most shops and businesses are closed that day, and though the Public Safety Bureau does not get holiday breaks, they toasted Ackerman in the office and ribbed him about getting old. He told everyone to go fuck themselves and amidst the laughter, Auruo whispered to Petra that Levi was the oldest after Smith.

They gave him the day off and Smith told Petra she could leave early too; work was slow. She bumped into Ackerman in the elevator on her way out and she doesn't remember exactly how the subsequent conversation went, but it ended with the two of them heading into a small café on a street corner, a few blocks away from the Bureau.

"It's okay that you're here, right?" she asks as they sit down; Ackerman picks up the menu and gives it a cursory glance. "Since you're with me. Technically we're not on duty but if an Enforcer is with an Inspector then—"

"Doesn't matter," Ackerman says, and then she doesn't know if she's just imagining things but she could swear he looks past her shoulder to stare straight at the scanner above the doorway. He raises one eyebrow briefly and then drops his gaze back to the menu in his hands and she decides it isn't her imagination after all.

"Why do you do that?"

"Do what?"

"It's like you're trying to get the system to notice you or something. Is it because of what happened in your last Division?"

He pauses in the middle of turning a page and she winces. She didn't mean to blurt that out, but she thinks of it every time he does something like that—which is quite often. There is something about Levi Ackerman's actions that is different from other Enforcers', and she wants to know what he is trying to achieve.

The words hang in the air between them, loaded with more questions than she meant to ask, and she wishes she could take them back—but then he only lifts one shoulder in a shrug. "Yeah," he admits, and something in the hoarse tone of his voice makes her breath catch. "It was almost a year ago. Last birthday I had, I spent it with them."

She hears what he does not say: _and now they're dead and I'm still alive, and there must be something wrong with the system for it to let that happen._ Sudden sadness for him and his lost friends squeezes her chest, making her heart ache, and she sits in silence for a moment, forcing herself to suppress the emotion (it's too much already, just being out with him, she can't let herself feel too much, she needs to remember her duty) before she speaks again.

"For what it's worth, Ackerman," she says, "I'm glad you're still here, and if that means the system's flawed, then I'm glad it is."

He considers her; the dim overhead lights of the establishment shine yellow on his pale face, obscuring the gray of his eyes with black. "Levi," he says.

"What?"

"Ackerman's a mouthful."

She grins. "Okay, Levi," she says, testing it out, "but then you have to call me Petra."

He nods, and though he does not say anything in response to her earlier comment, she knows he understands.

x.

"You're talking about the man who raised Levi."

She's stating the obvious so there is no answer, but she shakes her head in disbelief anyway. She picks up the pistol and fiddles with its safety catch for something to do, but she never fully flicks it off. "He failed though. Levi's been a latent criminal for most of his life."

"Only after his guardian disappeared," TITAN says. "In the first eight years of his life, Levi Ackerman's Psycho-Pass hue was as clear as his guardian's."

Petra stares at the small black barrel of the gun in her hands and tries not to picture the glass chambers behind her, but the images have been imprinted on her brain; she just knows the identity of one of the brains now. "So this guardian, he was made one of you."

"Criminally asymptomatic people are unpredictable," TITAN says, and Levi's words echo in her mind: _people are all the same, really. Predictable. It's easy to figure out what they all want._ "They are unable to be read by the system. If one tries to impart one's way of thinking to an impressionable mind, it is possible one can influence many others."

"So you want to study Levi too? Is that what you're saying?"

"He has a high potential for criminal activities but a certain restraint many others with his Crime Coefficient lack. There are not many latent criminals like him."

"But that doesn't even make sense. He killed someone who killed his friend; he tried to attack one of the Inspectors on his last team. Now he wants to take the system down. And his Crime Coefficient is just going to waver around 290 no matter what else he does?"

"The psychological effects of these events on his mind are what we determine his Crime Coefficient from."

"But a Crime Coefficient is supposed to be a person's likelihood for committing a crime—you are aware you're contradicting yourself, aren't you?" Her head is starting to pound again.

"Levi Ackerman is different," TITAN says; the voice is as robotic as ever but now she thinks there is a certain satisfaction in its tone as it adds, "He was Kenny Ackerman's last experiment, and he still is."

She lets out a shaky breath. "What the hell are you talking about now?"

"Do you think he would have been able to hack into the core of the system alone?"

x.

"I still can't believe he gave us the slip," Auruo sputters as they make their way down staircase after staircase; all the blueprints of Sina Tower display only a few levels below the ground floor but the wall in the supposed basement was open, revealing steps to many unaccounted levels below. "Just what the hell is he trying to do? And why the hell did he come _here_?"

"That's what we're going to find out," Petra says, trying not to sound too grim. She clutches the Dominator in her hand more tightly, reassuring herself with its weight.

She has heard stories of Enforcers gone rogue before, ones who tried to escape their duties—they were all caught, and if there were ones who hadn't been… well, she hasn't heard those stories. Those Enforcers' Crime Coefficients were never below 300 then, and she sincerely hopes for Levi's sake his still is.

She tries to ignore the larger part of her, the non-Inspector part, the part that's still a silly girl in training with idealistic views of the world, the part that feels betrayed. She thought they were getting along quite nicely, especially as of late, and though the last few months since his birthday have been nothing but harmonious, she should have kept in mind that he is a latent criminal, first and foremost.

But she doesn't want to think of him like that—he's just Levi, one of the Enforcers, Levi who drinks black coffee and smokes too many cigarettes and curses even when he's not angry. Levi, who took her to see a professor who could teach her about criminal profiling; Levi, who can one moment gun down criminals like they are nothing and then lower his weapon and try to comfort a woman the next. Levi, who smells too nice and stands too close and says her name in too soft a voice.

_Shut up and focus,_ she chides herself as she and the other three Enforcers turn down one last staircase. The true basement awaits them below, a long empty hallway leading to a door at the end. She eyes it curiously, remembering that this is where the core of TITAN is located. Normally they would have been stopped at the entrance, but the ground floor and all the levels they passed were curiously deserted.

"He's here," Gunter says, checking his mobile terminal. He points at the door, which is open a crack; light glows beyond. "He's just in there."

Petra raises her Dominator almost reluctantly as they approach. "Get ready," she says as the four of them move into position.

They lock eyes for a heartbeat, and then Petra steps forward and pushes open the door.

x.

"Even now," she whispers. "Even now he's being manipulated."

She thinks of the anger burning in his eyes, the absolute lack of emotion in his voice, the tension she could see in every part of his body—Levi does not become furious like most people. She thinks of the cold flat resolution he made, and the knowledge that even his rebellion is something the system wants makes her feel like something vital is missing from her heart.

"He does not know it, but he had help," TITAN continues to drone on. "Kenny Ackerman is still very interested in him. We all are—he is unique for a latent criminal, and to better prepare for all possibilities, we must gather as much data as possible."

"Shut up," she says. She can't stand how it's talking about Levi, like he can be summed up in a few inconsequential words, like he is nothing but just another step of a sick scientific procedure, just another hypothesis to be tested. "Just… shut up."

The voice falls silent and she realizes her hands are trembling faintly; she drops the pistol in case her fingers accidentally do something drastic with it. She takes several deep breaths and counts to ten; when she speaks again she thinks she is marginally calmer. "When are you going to be satisfied?" she spits. "When are you going to decide you've had enough and kill him?"

"If he becomes a true threat to the system, he will be eliminated," TITAN says.

"What if you can't find him? You don't know where he is right now. I know you don't know."

"We will find him."

"What if he succeeds? What if he actually brings the system down?"

"He will not."

"You never know. You practically admitted he has a few traits criminally asymptomatic people do; he might surprise you."

"He will not," TITAN repeats. She knows she is not imagining the superior air in its tone this time when it says, "Not as long as you are alive."

x.

"You can't. Levi, you know you can't."

"I should have known," he whispers. "I should have fucking known."

This is worse than anything she's encountered before; he has always been rather indifferent, but even when she didn't know him she could tell his face was not naturally made of stone. Now he is blank: not cold or hot with anger, but simply blank—blank, numb, and empty.

"You couldn't have known. No one knew. But Levi—you can't."

"Farlan died for nothing." He sounds so lifeless he could be commenting on the blue glow of the Dominator, but he is kneeling next to her by three pools of blood a few minutes ago she would have called friends; the Chief has disappeared. She does not wonder why they are still alive; she does not have time to wonder. "Auruo, Erd, and Gunter died for nothing."

_"Levi."_

He looks at her but his eyes do not see her. She grabs one of his hands in hers; the other still has a tight grip on the Dominator. "Levi, _listen to me_—you can't. We're detectives, remember? We solve crimes and protect people—_protect people_. The country has millions of people."

"Petra," he says.

She blinks when she realizes how close his face is to hers; she lets herself stare deep into his eyes, because no matter how hollow they are right now, anything is better than looking at the glass chambers behind them, the glass chambers full of dangerous truths. "What?" she says.

He says nothing, just presses his forehead to hers and closes his eyes, and when she feels wetness on her cheeks, she does not know if the tears are hers or his.

x.

"You told him you'd kill me if he does anything too extreme, didn't you." She doesn't know why the notion suddenly makes her want to laugh. "You threatened me to keep him in line."

"He cares for you," TITAN says. "He cares for you too much. It is a shame; you two would make a perfect pair."

It means an Inspector and Enforcer pair. She has to choke back a hysterical laugh bubbling in her throat. "How?"

"You work well together without influencing each other—his Crime Coefficient does not affect yours and your nature does not affect him. He is able to complete his tasks and you are able to complete yours, but there is a mutual trust rarely found between individuals in your respective stations."

"Too bad there can't be more people like us to continue upholding the system, right?" She picks up the Dominator and turns it over in her hands; the directionalized voice of TITAN that has been speaking to her all this time sounds louder when its source is in contact with her skin. She thinks of all the times she has shot people with TITAN's weapon and is suddenly, overwhelmingly relieved that it has never been in its lethal eliminator mode all those times.

"You agree that the system must be upheld and the truth of its existence withheld to maintain order in society."

"Yes, but that doesn't mean I agree with the system's existence in the first place. People will find out, you know. One day, people will find out, and everything's going to fall apart then."

"And that is why you will help us before that happens."

"I'm not helping you with anything." She feels more composed now; her heartbeat is thumping steadily, her mind feels sharp, and she speaks with coolheaded clarity. "I may not want to bring down the system and the country with it, but I'm not helping you with anything."

"You will. Before the public discovers the truth of the system's existence, we will reveal it, and you will help us, Petra Ral."

x.

She finds the letter and the pistol tucked inside the pocket of Levi's coat, which he's draped over her chair.

_You're right,_ the note says in his untidy scrawl. _I can't. But I have to try. I can't live without trying; I've doubted the system since I was old enough to know what it is and now that I finally know, I have to try. Don't doubt yourself, Petra; you're a true detective. If we ever meet again, do what you have to. Don't hesitate._

_You should know how old guns work from academy textbooks. Be careful with the safety catch._

It is very blunt, to-the-point; there is nothing fancy or eloquent about the note. It was written on a sheet of paper torn from a logbook. It is so very _Levi_ that she can feel herself tearing up again at the thought.

She just saw him earlier in the day; she was almost beginning to believe he might eventually be alright. It hasn't been a week since the incident below Sina Tower and already she feels fewer pangs of regret every time she looks at the empty desks in the office where three more Enforcers should sit; she feels equally relieved and guilty at the prospect of moving on.

She looks down at the note again and squeezes her eyes shut and counts to ten, telling herself not to cry. She is about to crumple the piece of paper in her fist when she notices scratched out words on the back.

_I'm glad I could work under you,_ he seems to have written before scribbling over the letters hastily in black ink.

Petra smiles even as she lets the tears fall.

x.

"So this is why you called me here," she realizes at last. "You told me Levi was here to get me to come. You told me about criminally asymptomatic people to see how I would react—but in the end you only want advice." She laughs, incredulous. "You're the system that judges people with a couple hundred brains; surely at least one of those brains can think of better advice than anything I might come up with."

"We want to study you, Petra Ral," TITAN says again and she shudders; she hates the way her name sounds in its computerized voice. "We will find the ideal way to reveal ourselves to the public from examining you and your interactions with others."

"So it's a warning too, then?" she wants to know. "'Be careful'? 'We'll be watching'?"

"It is information."

Petra picks up the pistol again and puts it back in her pocket; she won't be using it today. She holds the Dominator in both hands and stands to face the glass chambers; she wants to see who she is talking to, look upon the collective mind that has been speaking to her for the past hour and witness the truth of the system one last time. "Watch away then. I'll be doing my job."

"You know what is right," TITAN says. "You know your duty. Work for a better future."

She stares at the brains but she sees Levi's face, his dark gaze and indifferent expression and mouth twisted in a permanent scowl. She thinks of her aptitude for the Public Safety Bureau, of the hostage woman from her first mission kneeling in a pool of kerosene, of Auruo and Gunter and Erd and even Erwin Smith's father. She thinks of her civilian friends chatting over coffee, of the cases Division One has closed, of the drones and scanners lining every street. She thinks of her own clear Psycho-Pass hue and the finality of the Dominator's judgment and Levi's promise, and she smiles. It is not a pleasant smile.

"Oh, I will."

x.

When her mobile terminal goes off at two in the morning, she isn't asleep.

Her room has been pitch-black for nearly three hours but her mind has been awake for the same amount of time; she rolls over in bed and glances at the screen. _Unknown caller,_ it says. After a second's hesitation, she picks up.

"Inspector Ral speaking."

"You're alive. That's good."

She has not heard this particular voice in months now, and its sudden familiarity is startling. "Levi?" she breathes, hardly daring to believe it.

"I'm calling through remotely operated complex channels so there's no chance of being wiretapped, don't worry." He sounds better, she thinks, more alive—though anything has to be better than that dead voice he used in their last few days together.

"Where are you?" she says, then laughs at herself for asking. "Never mind. I'm glad you're alive too."

It is silent on his end of the line for a moment but she hears him breathing; she missed it, she thinks. She misses him. "It's why I'm calling," he says. "I'm alive now, but there's a lot of shit I need to do and if you find my corpse making a mess somewhere tomorrow… don't be surprised."

She considers for the briefest second telling him to come back, but she rejects that idea instantly; he wouldn't even if he were tempted. "That won't happen," she says with certainty.

"How do you know?"

It is her turn to be quiet now. She does not mention what she knows about TITAN; he does not tell her that he failed to expose the system the day he left to spare her life and she does not tell him that she knows. She listens to him breathe and she closes her eyes in the dark, content for this short period of time.

"I just know."

"Right, you're the top academy student; you know everything," he scoffs, and she can almost imagine that they are back in the office, she and Levi and Auruo and Erd and Gunter, teasing each other over their computer screens. She grins.

"Division One has a new Enforcer Ackerman, you know," she says. "Mikasa? Any relation of yours?"

"Never heard of her. Him?"

"Her. Smith's an Enforcer now too."

"Tell him and Hanji I said… better not, actually."

"Better not," she echoes.

There is a shuffling sound on the other end of the line; he must be moving around. "Who else is new?" he asks.

"Jaeger, Kirschtein, and Arlert—I'm the veteran Inspector now. They're even younger than when I first joined."

"Good luck with the brats," Levi says. She can practically hear his smirk.

"Good luck with whatever you're doing."

"Thank you," he says, voice lower, and she knows it is not merely her well wishes he is thanking her for.

They fall silent after that; there is not much she can say to him, she thinks, not through a mobile terminal. She needs to see him face-to-face again. "It's good to hear from you," she says. "Will you call again?"

"Probably not. It depends. If not… this'll be good-bye."

"No," Petra says. That is one thing she does not doubt, at least. "I'll see you again."

"Right," he says, and though it has been so long since they have spoken, she can tell he is not convinced. "Okay."

"I'm serious." She taps her fingers against her leg and recalls how often he used to do that; he probably still does. "We'll meet again. Not as Inspector Ral and Enforcer Ackerman, but as Petra and Levi. Okay?"

"Okay," he repeats, but this time she cannot tell what he is thinking from his tone of voice. "I should go now." There is a pause as he seems to struggle with words, and her grin widens: that hasn't changed; he will always be bad at displaying his emotions, whether physically or verbally. "See you, Petra," he finally says.

"See you, Levi."

He disconnects the call and she turns the screen off, leaving her room in darkness again. She stares up into the pitch-black of her ceiling and thinks of his first words to her, and then his latest, and she smiles because she is looking forward to the ones yet to come.

* * *

><p><em>AN: This fic was nice in my head; then I tried to write it out lmao. Oh well. Let me know if anything doesn't make sense; I have no idea how well I implied things._

_And yes I took the title from episode 18. Except nothing was written in water and 'Petra' means 'rock' so. Yeah._

_Also another scene from this AU can be found at suirenshi tumblr com/post/98644566349/ ('.' before and after 'tumblr')._


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